stool pigeon

American  

noun

1. a pigeon used as a decoy.

2. Also called stooly.  Also called stoolie.  Slang. a person employed or acting as a decoy or informer, especially for the police.

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stool pigeon British  

noun

1. a living or dummy pigeon used to decoy others

2. an informer for the police; nark

3. slang a person acting as a decoy

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stool pigeon Cultural  

1. An informer, especially for the police: “Lefty figured out that Mugsy was the stool pigeon when he saw him talking to the warden.”

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stool pigeon Idioms  

1. A decoy or informer, especially a police spy. For example, Watch out for Doug; I'm sure he's a stool pigeon for the supervisor. This term alludes to a bird tied to a stool or similar perch in order to attract other birds, which will then be shot. However, one writer believes that stool is a variant for stale or stall, both nouns used for a decoy bird before 1500 or so. [c. 1820]

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Etymology

Origin of stool pigeon

An Americanism dating back to 1820–30

Example Sentences

There is something about a healthy personality that feels repelled by a snoop, a snitch, a stool pigeon, an informer.

From Salon • Sep. 28, 2025

When the feds cracked down, Chicken of the Sea immediately turned stool pigeon of the sea and cooperated with the government to avoid prosecution.

From Slate • Aug. 17, 2020

In the end, Mr. Reles, who was known as “Kid Twist,” became a stool pigeon.

From New York Times • Oct. 14, 2016

Thordarson, for his part, tells me he thought he was helping to deliver a “notorious hacker” to the FBI, and didn’t know he was speaking to a fellow stool pigeon.

From Forbes • Jun. 28, 2013

"Never mind all that. Git that stool pigeon sober!"

From "Invisible Man" by Ralph Ellison